JPH07326456A - Resistance welding device for wire and method for connecting - Google Patents

Abstract

PURPOSE:To weld wires together in a mutually crossing pattern without moving them relative to each other by performing resistance welding with upper and lower electrodes abutting the crossing portions of wires which are made to cross each other and supported by a reception means and a holding means both of which have positioning grooves that cross each other. CONSTITUTION:When a holding means 21 is lowered using a hydraulic cylinder 51, wires 41, 43 are positioned in a mutually crossing pattern by the reception side positioning grooves 35, 37 of a reception means and by the holding side positioning grooves 55, 57 of the means 21. Under these conditions, resistance welding is carried out with a lower electrode 23 and an upper electrode 25 pressed into contact with the crossing portions of the respective wires 41, 43 so as to ensure that the wires are welded together in a mutually crossing pattern without moving relative to each other, resulting in the enhanced reliability of the welding connection.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric wire resistance welding apparatus and a connecting method for welding a pair of electric wires in a crossed state.

[0002]

2. Description of the Related Art FIG. 6 shows a state in which an end of an electric wire 3 is connected to a flat cable 1. When connecting the end of the electric wire 3 to the flat cable 1, the electric wire 3 is crossed with the flat cable 1 and the conductor 5 of the flat cable 1 and the conductor 7 of the end of the electric wire 3 are connected by welding. ing. As shown in FIGS. 7 (a) and 7 (b), when welding the electric wires 3 in a crossed state, the electric conductor 11 is provided in the middle of the electric wires 9.
Is exposed, the exposed portion is placed in the groove 13a of the lower electrode 13, the end of the electric wire 3 is placed in a state of intersecting the conductor portion, and then the upper electrode 15 is welded. In this way, by welding the lower electrode 13 and the upper electrode 15,
The electric wires 3 and 9 are connected in a crossing state.

[0003]

However, as shown in FIG. 8, when the conductor 7 of the other electric wire 3 is placed on the conductor 11 of the one electric wire 9 placed on the lower electrode 13. The welding position of the upper electrode 15 may be displaced. If the upper electrode 15 is welded in such a displaced state, as shown in FIG. 9, there is a problem in that an incompletely welded state cannot be obtained, and reliable connection cannot be achieved, resulting in a lack of reliability in connection.

Further, when welding is performed in such a displaced position, the welded portion adheres to the upper electrode 15 and moves with the movement of the upper electrode 15, as shown in FIG.

Further, when welding is performed with the position displaced,
Since the contact resistance becomes unstable, excessive heat may be generated locally, and the excessive heat may rupture and the wires may scatter.

Therefore, an object of the present invention is to provide an electric wire resistance welding apparatus and a connecting method in which a pair of electric wires are crossed and welded so that the position of the other electric wire is not displaced with respect to the other electric wire. To do.

[0007]

In order to achieve the above object, the invention according to claim 1 is a resistance welding device for an electric wire which crosses and welds a pair of electric wires, wherein one electric wire is accommodated and positioned. Receiving means, a holding means for positioning and holding the other electric wire placed on the one electric wire positioned on the receiving means in an intersecting state, and an intersecting portion of the pair of electric wires. And a lower electrode for supporting the lower part of the above, and an upper electrode for positioning and holding the other electric wire by the pressing means and then abutting the upper part of the intersecting portion and welding the intersecting portion together with the lower electrode.

A second aspect of the present invention is the invention according to the first aspect, in which the cradle is fixed to the cradle and
The receiving means is formed from a soft receiving member in which a receiving side positioning groove for accommodating a pair of electric wires is formed, and a pressing base that can be contacted with and separated from the receiving base, and is fixed to the pressing base, It is characterized in that the pressing means is formed by a soft pressing member having a holding side positioning groove for receiving a pair of electric wires housed in the receiving side positioning groove.

A third aspect of the present invention is the invention according to the second aspect, wherein the lower electrode penetrates the soft receiving member and abuts a lower portion of an intersecting portion of the pair of electric wires, and the upper electrode holds the soft pressing member. It is characterized in that it penetrates through the member and comes into contact with the upper portion of the intersection of the pair of electric wires.

The invention of claim 4 is the invention of claim 2 or claim 3.
In the invention described above, the lower electrode penetrates the pedestal and abuts a lower side of a crossing portion of a pair of electric wires, and the upper electrode penetrates the holding base and an upper portion of a crossing portion of the pair of electric wires. And a cooling means for cooling the welded portion and its periphery are provided on at least one of the receiving base and the pressing base.

A fifth aspect of the present invention is the invention according to the fourth aspect, characterized in that the cooling means is a cooling refrigerant that circulates inside at least one of the holding base and the receiving base.

A sixth aspect of the present invention is a connecting method for crossing and welding a pair of electric wires, wherein one electric wire is positioned and mounted on the receiving means, and the other electric wire is crossed on the one electric wire. After placing in a state, the periphery of the intersection of the pair of electric wires is positioned and held between the receiving means and the receiving means, and after contacting the lower electrode to the lower part of the intersection, It is characterized in that the upper electrode is brought into contact with the above electrode and the intersecting portion is welded.

The invention according to claim 7 is the invention according to claim 6, wherein after welding the intersections of the upper electrode and the lower electrode,
It is characterized in that the upper electrode is separated from the intersecting portion while the periphery of the intersecting portion is positioned and held by the receiving means and the holding means.

The invention of claim 8 is claim 6 or claim 7.
The invention described in (1) is characterized in that the intersection of a pair of electric wires is welded by the upper electrode and the lower electrode while cooling the welded portion and the periphery thereof.

[0015]

According to the first aspect of the present invention, after one electric wire is positioned and accommodated in the receiving means, the other electric wire is placed in a state intersecting with the electric wire and the holding means positions and holds the electric wire. From this state, the lower part of the intersection of one electric wire and the other electric wire is supported by the lower electrode, and the upper electrode is brought into contact with the upper part of the intersection. Then, the intersections are connected by welding.

According to the second aspect of the invention, one of the electric wires is accommodated in the receiving side positioning groove of the soft receiving member on the pedestal, and in this state, the other electric wire is placed in a state of intersecting the one electric wire. Place. Next, in a state where the other electric wire is accommodated in the holding side positioning groove of the soft pressing member fixed to the pressing base, the circumference of the intersection of the one electric wire and the other electric wire is supported between the other electric wire and the soft receiving member. From this state, the lower part of the intersection is supported by the lower electrode, and the upper electrode is brought into contact with the upper part of the intersection. Then, the intersections are connected by welding.

According to the third aspect of the invention, the lower electrode penetrating the soft receiving member in the crossing portion of the crossing portion of the electric wire is supported between the soft receiving member and the soft pressing member while supporting the periphery of the crossing portion of the pair of electric wires. The upper electrode supporting the lower portion and penetrating the soft pressing member is brought into contact with the upper portion of the intersecting portion. Then, the intersections are connected by welding.

According to the fourth aspect of the present invention, when the lower electrode supports the lower portion of the intersecting portion of the pair of electric wires and the upper electrode is brought into contact with the upper portion of the intersecting portion for welding, the welding is performed by the cooling means. The part and its surroundings are cooled. This suppresses the temperature rise of the welded portion and its surroundings.

According to the fifth aspect of the invention, when welding the crossing portion of the pair of electric wires, by circulating the cooling refrigerant inside at least one of the holding base and the receiving base, the welded portion and its periphery are circulated. Temperature rise is suppressed.

According to the sixth aspect of the present invention, one electric wire is positioned and placed on the receiving means, and the other electric wire is placed on the one electric wire in a crossed state. Next, the lower electrode is brought into contact with the lower portion of the intersecting portion and the upper electrode is brought into contact with the upper portion thereof in a state of being supported between the receiving means and the holding means around the intersection portion of the pair of electric wires. Then, the intersections are connected by welding.

According to the seventh aspect of the invention, the upper electrode is separated from the upper portion of the intersecting portion while being held between the receiving means and the holding means around the intersecting portion. This prevents the intersecting portion from moving together with the upper electrode in a state where the intersecting portion is adhered to the upper electrode.

According to the eighth aspect of the present invention, when welding a crossing portion of a pair of electric wires, by welding while cooling the welded portion and its periphery, it is possible to suppress the temperature rise.

[0023]

EXAMPLES Examples of the resistance welding apparatus and connection method for electric wires according to the present invention will be described below.

[0024] The resistance welding device and connection method of the first embodiment the first embodiment will be described. 1 is a perspective view showing the resistance welding apparatus of the embodiment,
2 (a), 2 (b), 3 (a), 3 (b), and 3 (c) are cross-sectional views showing the procedure of the connection method.

As shown in FIGS. 1 and 2, the resistance welding apparatus 17 of this embodiment includes a receiving means 19 and the receiving means 19.
The pressing means 21 which can be brought into and out of contact with the lower electrode 2 and the lower electrode 2 which penetrates the receiving means 19 and abuts on the lower portion of the intersection of the pair of electric wires.
3 and an upper electrode 25 penetrating the holding means 21 and capable of coming into contact with and separating from the lower electrode 23.

The receiving means 19 comprises a receiving table 27 and a soft receiving member 29 fixed to the receiving table 27. At the center of the cradle 27 and the soft receiving member 29,
A through hole 33 opening to the receiving surface (upper surface) 31 of the soft receiving member 29 is formed, and the lower electrode 23 is inserted and arranged in the through hole 33. The upper end surface of the lower electrode 23 is flush with or slightly above the opening surface of the through hole 33. In the soft receiving member 29, two semicircular receiving side positioning grooves 35 and 37 are formed in an intersecting state. These receiving side positioning grooves 35, 37
The opening 39 is formed at the intersection of the. The size of these receiving side positioning grooves 35, 37 is equal to that of the electric wires 41, 4
It is formed to have a diameter of about 1/2 of 3, and the electric wires 41 and 43 are positioned by accommodating the electric wires 41 and 43 as shown in FIG. Also, the receiving side positioning groove 3
The intersecting portion 45 of the pair of electric wires 41 and 43 housed in the Nos. 5 and 37 is located not only on the opening 39 but also on the upper end surface of the lower electrode 23. These receiving side positioning grooves 35, 3
The pair of electric wires 41 and 43 accommodated in the
Are held and supported by the soft receiving member 29 while being positioned between them.

The pressing means 21 comprises a pressing base 47 and a soft pressing member 49 fixed to the lower side of the pressing base 47. The presser base 47 is connected to the tip end portion of the drive shaft 51 a of the hydraulic cylinder 51, moves up and down by the operation of the hydraulic cylinder 51, and comes into contact with and separates from the receiving means 19. In addition, a through hole 53 that opens to the lower surface side of the soft pressing member 49 is formed in the center of the presser base 47 and the soft pressing member 49, and the upper electrode 25 can move up and down in the through hole 53. Has been inserted into. The upper electrode 25 is supported by a driving means such as a hydraulic cylinder so as to be movable up and down, and a pressing base 47 is provided.
And the soft pressing member 49 moves up and down independently of the up and down movement.

On the lower surface side of the soft pressing member 49, two semicircular pressing side positioning grooves 55 and 57 are formed in a state of intersecting with each other. These presser side positioning grooves 55, 57
The opening 59 of the through hole 53 is formed at the intersection of the. The size of the holding side positioning grooves 55, 57 is formed to be about ½ of the diameter of the electric wires 41, 43. When the soft pressing member 49 is in contact with the soft receiving member 29, the receiving side positioning grooves 35 and 37 and the pressing side positioning grooves 55 and 57 are combined to form a circular through hole. The electric wires 41 and 43 placed on 35 and 37 are housed in the holding-side positioning grooves 55 and 57. As a result, the pair of electric wires 41, 43 are connected to the soft receiving member 2
9 and the soft pressing member 49 are sandwiched, supported, and positioned.

Next, a connection method for connecting a pair of electric wires in a crossing state by the resistance welding device 17 will be described.

As shown in FIG. 2A, one electric wire 41
The conductive body 61 of the receiving side positioning groove 3 of the soft receiving member 29.
Place on 5. Next, the conductor 63 of the other electric wire 43 is accommodated on the one electric wire 41 and in the receiving side positioning groove 37. In this state, the intersection 45 of the pair of electric wires 41 and 43 is located above the opening of the soft receiving member 29.

From this state, the hydraulic cylinder 51 is operated to lower the presser base 47 and bring the soft presser member 49 into contact with the soft receiver member 29. At this time, the pair of electric wires 4
Around the intersection 45 of the first and the third portions 43, the receiving side positioning groove 3 is formed.
5 and 37 and the holding side positioning grooves 55 and 57 are held in a state of being positioned. The lower portion of the intersecting portion 45 is located in the opening 39 and abuts on the upper end surface of the lower electrode 23, and the upper portion of the intersecting portion 45 is located in the opening 59.

Then, the upper electrode 25 is lowered and brought into contact with the upper portion of the intersecting portion 45 and welded, whereby the intersecting portion 45 is welded and electrically connected.

Next, the soft receiving member 29 and the soft pressing member 49
While holding the periphery of the intersection 45, the upper electrode 2
5, the presser base 47 and the soft pressing member 49 are moved upward, and then the intersecting portion 45 is moved to the soft receiving member 29.
Take out from above.

According to this embodiment, a pair of electric wires 41, 43
Around the intersection of the soft receiving member 29 and the soft pressing member 4
Since it is sandwiched by 9 and positioned, the intersecting portion 45 does not shift from the upper end surface of the lower electrode 23 and the end surface of the upper electrode 25, and the intersecting portion 45 can be reliably welded.
As a result, the reliability of the electrical connection at the intersection can be improved.

The intersection 4 of the pair of electric wires 41, 43
Since the connection is not made at a position deviated from 5, the electric wire does not come apart and is not partially heated. Therefore, it does not generate excessive heat and does not burst and scatter. Therefore, the work can be performed safely.

Further, since the upper electrode 25 is raised and separated from the intersecting portion 45 while the periphery of the intersecting portion 45 is held by the soft receiving / receiving member 29 and the soft pressing member 49, the intersecting portion 45 becomes the upper electrode 25. It does not move in a bonded state.

Second Embodiment Next, a resistance welding apparatus and a connecting method according to a second embodiment will be described. The same components as those in the first embodiment are designated by the same reference numerals in the drawings, and duplicated description will be omitted. In the resistance welding device 65 of the present embodiment, a holding table 67 is provided with a cooling means 69 for cooling the welded portion and its periphery.

As shown in FIGS. 4 and 5 (a) and 5 (b), the inside of the presser base 67 of this embodiment is hollow so that a circulation chamber 71 is formed. Further, the inside of the drive shaft 51a of the hydraulic cylinder 51 is also formed to be hollow, and the circulation chamber 7
It is in communication with 1. The drive shaft 51a is provided in the circulation chamber 71.
The cooling refrigerant 73 (water, air, or the like) supplied to the inside of the is circulated.

Then, the conductor 61 of the one electric wire 41 is placed on the receiving side positioning groove 35 of the soft receiving member 29, and the conductor 63 of the other electric wire 43 is placed on the receiving side positioning groove 37. In this state, the intersection 4 of the pair of electric wires 41, 43
5 is located on the opening of the soft receiving member 29.

From this state, the hydraulic cylinder 51 is operated to lower the presser base 67, and the soft presser member 49 is brought into contact with the soft receiver member 29. At this time, the pair of electric wires 4
Around the intersection 45 of the first and the third portions 43, the receiving side positioning groove 3 is formed.
5 and 37 and the holding side positioning grooves 55 and 57 are held in a state of being positioned. Then, the upper electrode 25 is lowered, brought into contact with the upper portion of the intersecting portion 45, and welded, whereby the intersecting portion 45 is welded and electrically connected.

At the same time, the circulation chamber 71 in the presser base 67
The cooling refrigerant 73 is circulated therein. This suppresses an increase in the temperature of the presser base 67, cools the heat generated when welding the intersecting portion 45 of the pair of electric wires 41, 43, and cools the intersecting portion (welding portion) 45 and its surroundings. . That is, by circulating the cooling medium 73 in the circulation chamber 71 to cool the presser base 67 to which the heat generated during welding is transmitted, the heat of the intersecting portion 45 is removed, and the heat of the intersecting portion 45 is removed. Suppress. Further, the heat around the intersecting portion 45 can be suppressed by cooling the presser base 67.

According to this embodiment, in addition to the same effects as those of the first embodiment, the cooling refrigerant 73 is circulated in the circulation chamber 71 in the presser base 67, so that the welded portion and its surroundings can be obtained. It is possible to suppress the heat generation. Therefore, partial excessive heat generation is prevented, and the electric wires do not scatter due to excessive heat generation. In addition, the insulating portion is not melted by heat, the insulating property is maintained, and stable electrical connection is obtained.

[0043]

As described above, according to the first aspect of the present invention, the lower electrode and the upper electrode are connected in a state in which the periphery of the intersection of the pair of electric wires is positioned and held by the receiving means and the pressing means. It is possible to reliably connect a pair of electric wires in a crossed state without welding in a state where the connection positions are displaced. Therefore, reliability in electrical connection can be improved.

According to the second aspect of the present invention, the pair of electric wires are housed in the positioning grooves of the soft receiving member and the soft pressing member in a crossed state, and the periphery of the crossing portion of the pair of electric wires is supported. The welding position by the lower electrode does not shift, and the pair of electric wires can be reliably connected in a crossed state. Further, when supporting the periphery of the crossed electric wire, since the soft receiving member and the soft pressing member are used, it is possible to surely hold the periphery of the intersection without damaging the periphery.

According to the third aspect of the present invention, the lower portion of the intersecting portion is fixed to the lower portion of the intersecting portion by the lower electrode penetrating the soft receiving member while supporting the periphery of the intersecting portion of the pair of electric wires between the soft receiving member and the soft pressing member. Since the upper electrode that supports and penetrates the soft pressing member is brought into contact with the upper part of the intersection, the position of the intersection of the pair of electric wires does not shift with respect to the lower electrode and the upper electrode, and the intersection is securely connected. You can do it.

According to the fourth aspect of the present invention, when the lower electrode supports the lower portion of the intersecting portion of the pair of electric wires and the upper electrode is brought into contact with the upper portion of the intersecting portion for welding, the pressing base is cooled by the cooling means. Alternatively, since at least one of the pedestals is cooled, the welded part and its surroundings are cooled, and the temperature rise of the welded part and its surroundings is suppressed. Therefore, excessive heat generation in the welded portion is prevented, and the electric wire does not scatter due to rupture.

According to the fifth aspect of the present invention, when welding the intersection of the pair of electric wires, the cooling refrigerant circulates inside at least one of the holding base and the receiving base. The rise is suppressed, and overheating can be prevented.

According to the sixth aspect of the present invention, after the pair of electric wires are placed on the receiving means in an intersecting state, the lower electrode and the upper electrode are supported in a state of supporting the periphery of the intersecting portion of the pair of electric wires by the holding means. Since the welding is performed with and, the connection position between the lower electrode and the upper electrode does not shift, and the intersecting portion can be reliably connected.

According to the invention of claim 7, the upper electrode is separated from the upper portion of the intersecting portion while being held between the receiving means and the holding means around the intersecting portion, so that the intersecting portion is bonded to the upper electrode. It does not move together with the upper electrode in this state.

According to the eighth aspect of the present invention, when welding a crossing portion of a pair of electric wires, by welding while cooling the welded portion and its periphery, it is possible to suppress the temperature rise, and the welded portion and It is possible to prevent excessive temperature rise by suppressing an increase in the temperature of the surrounding area.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of a resistance welding apparatus according to the present invention.

2A and 2B show a procedure of a connection method according to a first embodiment of the present invention, FIG. 2A is a sectional view showing a state in which a pair of electric wires are accommodated in a receiving side positioning groove, and FIG. FIG. 6 is a cross-sectional view showing a state in which a soft pressing member is pressed to support the periphery of an intersecting portion of a pair of electric wires.

FIG. 3 shows a procedure of a connecting method of a first embodiment according to the present invention, (a) shows that a lower electrode supports a lower part of an intersection of a pair of electric wires, and an upper electrode abuts on an upper part of the intersection. Sectional view showing a state in which the upper electrodes are lifted and separated from the connecting portion after connecting the intersecting portions of the pair of electric wires, and (c) is a sectional view showing the pair of electric wires. FIG. 6 is a cross-sectional view showing a state in which, after connecting the intersecting portions, the presser base is raised to separate the soft pressing member from the soft receiving member.

FIG. 4 is a perspective view showing a second embodiment of the resistance welding apparatus according to the present invention.

5A and 5B show a connecting method in the resistance welding apparatus of the second embodiment, wherein FIG. 5A is a cross-sectional view showing a state before welding a crossing portion of a pair of electric wires, and FIG. 5B is a crossing portion of a pair of electric wires. It is sectional drawing which shows the state which is welding.

FIG. 6 is a perspective view showing a conventional state in which electric wires are connected to a flat cable in a crossed state.

FIG. 7A is a perspective view showing a state in which a pair of electric wires are welded at a crossing portion, and FIG. 7B is a perspective view showing a conventional upper electrode and a lower electrode which are welded in a state where the electric wires are crossed.

FIG. 8 is a side view showing a state in which an intersecting portion of an electric wire is deviated between an upper electrode and a lower electrode.

FIG. 9 is a side view showing a state in which the upper electrode and the lower electrode are welded in a state where the positions of the upper electrode and the lower electrode are displaced with respect to the intersecting portion of the electric wire.

FIG. 10 is a side view showing a state in which a welded portion of a pair of electric wires is adhered to an upper electrode.

[Explanation of symbols]

 17, 65 Resistance welding device 19 Receiving means 21 Holding means 23 Lower electrode 25 Upper electrode 27 Receiving table 29 Soft pressing member 35, 37 Receiving side positioning groove 41, 43 Electric wire 45 Intersection 47, 67 Pressing table 49 Soft pressing member 55, 57 Presser side positioning groove 69 Cooling means 71 Circulating chamber 73 Cooling refrigerant

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[Procedure amendment]

[Submission date] February 9, 1995

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

Claims (8)

[Claims] 1. A resistance welding device for an electric wire for welding a pair of electric wires crossing each other, comprising: receiving means for accommodating and positioning one electric wire; and one electric wire positioned on the receiving means. Holding means for positioning and holding the other electric wire placed in an intersecting state with the receiving means, a lower electrode for supporting the lower part of the intersection of the pair of electric wires, and positioning the other electric wire by the holding means. A resistance welding apparatus for an electric wire, comprising: an upper electrode that holds the upper portion of the intersecting portion after being held and welds the intersecting portion together with the lower electrode. 2. The invention according to claim 1, wherein the pedestal and a soft receiving member fixed to the pedestal and having a receiving side positioning groove for accommodating a pair of electric wires are formed. A pressing base that forms a receiving means and can be brought into and out of contact with the receiving base, and a pressing-side positioning groove that is fixed to the pressing base and that accommodates the pair of electric wires accommodated in the receiving-side positioning groove are provided. A resistance welding device for an electric wire, characterized in that the pressing means is formed with the formed soft pressing member. 3. The invention according to claim 2, wherein the lower electrode penetrates the soft receiving member and abuts on a lower portion of an intersecting portion of the pair of electric wires, and the upper electrode penetrates the soft pressing member. A resistance welding device for an electric wire, which is in contact with an upper portion of an intersecting portion of the pair of electric wires. 4. The invention according to claim 2 or 3, wherein the lower electrode penetrates the receiving base and abuts on a lower side of a crossing portion of a pair of electric wires, and the upper electrode holds the pressing base. And abutting on the upper side of the intersecting portion of the pair of electric wires, and at least one of the receiving base or the pressing base is provided with cooling means for cooling the welded portion and its surroundings. Welding equipment. 5. The electric wire resistance welding apparatus according to claim 4, wherein the cooling means is a cooling refrigerant that circulates inside at least one of the holding base and the receiving base. 6. A connection method for welding a pair of electric wires by crossing them, wherein one electric wire is positioned and placed on a receiving means.
After the other electric wire is placed on the one electric wire in an intersecting state, the periphery of the intersecting portion of the pair of electric wires is positioned and held between the receiving means and the receiving means, and the lower electrode is provided under the intersecting portion. After contacting, the upper electrode is brought into contact with the upper portion of the intersecting portion, and the intersecting portion is welded to the lower electrode. 7. The invention according to claim 6, wherein after welding the intersection between the upper electrode and the lower electrode, the periphery of the intersection is positioned and held by the receiving means and the holding means. 2. The connection method characterized in that the upper electrode is separated from the intersecting portion by. 8. The invention according to claim 6 or 7, wherein the intersection of a pair of electric wires is welded by the upper electrode and the lower electrode while cooling the welded portion and its periphery. And connection method.